Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F42—AMMUNITION; BLASTING
  • F42B—EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION
  • F42B12/00—Projectiles, missiles or mines characterised by the warhead, the intended effect, or the material
  • F42B12/02—Projectiles, missiles or mines characterised by the warhead, the intended effect, or the material characterised by the warhead or the intended effect
  • F42B12/04—Projectiles, missiles or mines characterised by the warhead, the intended effect, or the material characterised by the warhead or the intended effect of armour-piercing type
  • F42B12/06—Projectiles, missiles or mines characterised by the warhead, the intended effect, or the material characterised by the warhead or the intended effect of armour-piercing type with hard or heavy core; Kinetic energy penetrators
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F42—AMMUNITION; BLASTING
  • F42B—EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION
  • F42B12/00—Projectiles, missiles or mines characterised by the warhead, the intended effect, or the material
  • F42B12/72—Projectiles, missiles or mines characterised by the warhead, the intended effect, or the material characterised by the material
  • F42B12/76—Projectiles, missiles or mines characterised by the warhead, the intended effect, or the material characterised by the material of the casing
  • F42B12/78—Projectiles, missiles or mines characterised by the warhead, the intended effect, or the material characterised by the material of the casing of jackets for smallarm bullets ; Jacketed bullets or projectiles
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T29/00—Metal working
  • Y10T29/49—Method of mechanical manufacture
  • Y10T29/49803—Magnetically shaping
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T29/00—Metal working
  • Y10T29/49—Method of mechanical manufacture
  • Y10T29/49826—Assembling or joining
  • Y10T29/49908—Joining by deforming
  • Y10T29/49925—Inward deformation of aperture or hollow body wall
  • Y10T29/49927—Hollow body is axially joined cup or tube
  • Y10T29/49929—Joined to rod

Definitions

• the present invention relates to a perforating projectile of caliber less than or equal to 40 mm.
• the invention also relates to a cartridge comprising such a perforating projectile as well as the method for the manufacture thereof.
• the known .perf rants projectiles most often comprise a metal or ductile alloy covering such as copper or brass which surrounds a metal core such as hardened steel or tungsten carbide embedded in lead.
• the core of the piercing projectile has on its rear part a Morse cone which is fitted into a complementary cone formed in a guide or shoe made of ducti metal which thus comes partially cover the hard core.
• This assembly method makes it possible to obtain good conditions for rotating the core.
• This projectile thus has a satisfactory perforating power.
• this method of assembly by Morse cones or self-tightening cones is hardly compatible with industrial mass production. Indeed, the machining of Morse cones must be carried out with great precision to obtain a perfect and seamless interlocking between the guide and the rear face of the core.
• undulations are made on the outer face of the guide in order to limit the friction between this outer surface and the scratches formed inside the barrel of the shooting weapon.
• the object of the present invention is to remedy the drawbacks of known embodiments, by creating a perforating projectile in which the core and the guide are linked together in such a way that the rotation takes place under optimal conditions and in which the guide has on its outer surface corrugations which reduce the friction of the projectile inside the barrel of the shooting weapon, such a projectile is easy and inexpensive to manufacture.
• the perforating projectile of caliber less than or equal to 40 mm aimed by the invention comprises a core having a front point, this core being of a hard or high density metal or metal alloy, surrounded at the rear of its point by a generally cylindrical guide of ductile metal, the part of the core which is surrounded by the guide having projections and recesses the guide being crimped on this part of the core by radial compression so that the inner surface of the guide is linked axially and in rotation on said part of the core via the projections and recesses of the latter.
• this projectile is characterized in that the guide is crimped onto said part of the core by electromagnetic forming and in that said part of the core has undulations, the inner surface of the guide in contact with said part of the core conforming to the profile of this undulations and the outer surface of the guide reproducing the profile of these undulations, the shape of these undulations being predetermined so that those reproduced on the outer surface of the guide present the desired ballistic properties.
• ductile metal is meant a metal or alloy more ductile than the steel of the barrel of the shooting weapon.
• Crimping by electromagnetic forming consists in introducing the core covered with the guide into a solenoid.
• the magnetic field generated by this solenoid develops intense forces (Laplace Forces) for a few microseconds which not only compress the guide radially on the nucleus, but also allow to obtain a true weld, by diffusion of atoms, between this guide and the core.
• ductile metal such as copper or an alloy such as brass for the guide and steel for the core is optimal for the implementation of electromagnetic forming.
• this electromagnetic forming thus makes it possible to obtain an excellent bond between the guide and the core, while being perfectly suited to industrial mass production. Indeed, the dimensions of the guide and of the core do not need to be adjusted with very great precision, since the deformations generated during crimping compensate for dimensional deviations.
• the method for manufacturing the projectile in accordance with the invention preferably comprises the following steps: - a core is produced having behind the point, a substantially cylindrical part of reduced diameter and having hollows and protrusions,
• a guide of generally cylindrical shape is produced, the internal diameter of which is substantially equal to or slightly greater than the diameter of the part of the core which is intended to be surrounded by the guide,
• the guide is engaged on said substantially cylindrical part of the core
• the guide is crimped onto said sensiblem cylindrical part of the core by electromagnetic forming, so that the outer surface of the guide reproduces the profile of the hollows and projections of the aforementioned part of the core. So in starting from a cylindrical guide, it is possible to obtain a single operation which does not require any additional machining, a perfect mechanical connection between the guid and the core and to obtain on the surface of the guide the corrugated profile sought to reduce friction inside the barrel without affecting the ballistic properties of the projectile.
• FIG. 1 is a plan view of the core and in longitudinal section of the guide of a projectile conforming to
• FIG. 3 is a longitudinal sectional view guide engaged on the core, the assembly being introduced into the solenoid of an electromagnetic forming device
• FIG. 4 is an elevational view with cutaway, of a cartridge according to l 'invention.
• the perforating projectile of caliber less than or equal to 40 mm comprises a core 1 having a front point 2 of conventional ogival shape.
• This core 1 is made of a metal or hard and / or high density metal alloy such as hardened steel and is surrounded at the rear of its tip by a guide 3 of shape general cylindrical in ductile metal, such as copper or brass.
• the part 4 of the core 1 which is surrounded by the guide 3 has projections 5 and recesses 6 and the guide is crimped onto this part 4 of the core by radial compression, so that the inner surface of the guide is linked axially and in rotation to said part 4 of the core via the projections 5 and the recesses 6 of the latter.
• the guide 3 is crimped on the p of the core 1 by electromagnetic forming.
• the ogival tip 2 d core is connected to the part 4 surrounded by the guide 3, by an annular shoulder 7 whose radial width corresponds substantially to the thickness e of the wall of the mistletoe 3, the edge of the latter being in abutment against this shoulder 7.
• projections 5 and the recesses 6 formed on part 4 of the core consist of annular undulations and the internal surface of the guide 3 in contact with this part 4 of the no. these ripples.
• the outer surface of the guide 3 has corrugations 8 which follow the profile of the corrugations 5 formed on the part 4 of the core.
• the profile of these corrugations 5 is predetermined as a function of the profile sought for the external corrugations 8 of the guide.
• the maximum diameter di of the pointed tip 2 is slightly lower than the through caliber of the barrel of the projectile firing arm.
• the maximum diameter d4 of the part 4 of the core 1 is less than the diameter di so that the thickness e_ of the wall of the guide 3 is sufficient to allow its deformation when it comes into engagement with the scratches of the barrel of the weapon shooting.
• This thickness e is of the order of
• the amplitude of the corrugations 8 is between 0.5 and 1 mm
• the corrugations 5 formed on the part 4 of the core 1 are such that the maximum diameter d is equal to d2 - 2e (d2 being equal to the caliber of the projectile) and that the minimum diameter ds of the guide is equal to d3 - 2e (d3 being equal to the minimum diameter of the guide which is equal to di in the example of FIG. 1).
• the corrugations 8 the profile of which is formed in the example of FIG. 1 by successively concave or convex equal arcs of circle, comprise at least two arcs forming bumps which ensure perfect guidance of the projectile inside the barrel, all by limiting friction. Furthermore, the amplitude of these undulations 8 is sufficiently small and their radius is large enough not to affect the aerodynamic properties of the projectile.
• the part 4 of the core 1 has, opposite the tip 2, a substantially frustoconical surface 9, the small base 10 of which coincides with the rear end of this part.
• the inner surface of the guide 3 has a substantially frustoconical surface complementary to this substantially frustoconical surface of the part 4 of the core and the mistletoe 3 has a rear wall 11 pressed against the rear end 10 of the core 1.
• This process comprises the following stages: a core 1 is produced having at the rear part of its tip 2 a substantially cylindrical part of reduced diameter and having hollows 6 and projections 5, obtained for example by turning,
• a guide 3 is produced of generally cylindrical shape whose maximum internal diameter of is substantially equal to or slightly greater than the maximum diameter d of the part 4 of the core which is intended to be surrounded by the guide 3.
• the length li of the internal cavity of the guide 3 is slightly less than the length I2 of the part 4 of the core,
• the guide 3 is then engaged on the substantially cylindrical part 4 of the core 1 and the guide 3 is crimped on this substantially cylindrical part 4 of the core by electromagnetic forming, by means of the device shown diagrammatically in FIG. 3.
• This device comprises a solenoid 13 surrounding guide 3 engaged on part 4 of the core 1.
• This solenoid 13 is connected to a generator 14 of electric current.
• Parallel to the terminals of the solenoid 13 is a capacitor 15.
• the electrical circuit further includes a charge switch 16 and a discharge switch 17.
• the solenoid 13 When the charge switch 16 and then the discharge switch 17 are closed, the solenoid 13 is traversed by a current of damped sinusoidal shape and a variable magnetic field is created inside the solenoid. This magnetic field generates a force which compresses the guide 3 radially on the part 4 of the core.
• the radial pressure exerted on the guide is substantially given by a relation of the ty
• the copper or brass used for the guide 3 e the steel used for the core 1 form a pair of ideal materials for the implementation of the electromagnetic forma process.
• the core steel is preferably Z 85 DCV 6542 steel.
• Another advantage of this process lies in the fact that it allows, in a single operation, to reproduce on the surface of the guide 3 the undulations which make it possible to limit the friction inside the barrel of the shooting weapon.
• the guide 3 can be obtained from a simple drawn tube.
• the undulations made in the core do not need to be machined with precision, c the electromagnetic forming gives the undulations of the gu a smooth surface, even if the undulations of the core are not not machined with great precision.
• a surface of the core not precisely machined, leaving micro-roughness, is favorable to the adhesion between the guide and the core.
• the shape of the corrugations formed on the part 4 of the core 1 may be different from that shown in FIG. 1.
• the guide 3 could be devoid of bottom and produced from a simple drawn tube, which makes it possible to further reduce the manufacturing costs.

Landscapes

• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Powder Metallurgy (AREA)
• Shielding Devices Or Components To Electric Or Magnetic Fields (AREA)
• Aiming, Guidance, Guns With A Light Source, Armor, Camouflage, And Targets (AREA)
• Stringed Musical Instruments (AREA)
• Paper (AREA)
• Inks, Pencil-Leads, Or Crayons (AREA)
• Moulds For Moulding Plastics Or The Like (AREA)
• Physical Vapour Deposition (AREA)
• Toys (AREA)
• Soft Magnetic Materials (AREA)

Priority Applications (5)

Applications Claiming Priority (2)

Publications (1)

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Citations (4)

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• 1987
  • 1987-02-11 FR FR8701691A patent/FR2610715A1/fr active Pending
• 1988
  • 1988-02-05 AU AU12929/88A patent/AU596504B2/en not_active Ceased
  • 1988-02-05 AT AT88400271T patent/ATE56815T1/de not_active IP Right Cessation
  • 1988-02-05 BR BR8805262A patent/BR8805262A/pt unknown
  • 1988-02-05 DE DE198888400271T patent/DE279732T1/de active Pending
  • 1988-02-05 EP EP88400271A patent/EP0279732B1/de not_active Expired - Lifetime
  • 1988-02-05 DE DE8888400271T patent/DE3860615D1/de not_active Expired - Fee Related
  • 1988-02-05 WO PCT/FR1988/000064 patent/WO1988006266A1/fr active Application Filing
  • 1988-02-05 US US07/275,134 patent/US4878434A/en not_active Expired - Fee Related
  • 1988-02-05 KR KR1019880701257A patent/KR930000303B1/ko active IP Right Grant
  • 1988-02-05 ES ES88400271T patent/ES2003843B3/es not_active Expired - Lifetime
  • 1988-02-08 PT PT86722A patent/PT86722B/pt not_active IP Right Cessation
  • 1988-02-08 MA MA21417A patent/MA21180A1/fr unknown
  • 1988-02-08 ZA ZA880869A patent/ZA88869B/xx unknown
  • 1988-02-09 IL IL85373A patent/IL85373A0/xx unknown
  • 1988-02-09 YU YU00244/88A patent/YU24488A/xx unknown
  • 1988-02-09 IN IN114/CAL/88A patent/IN167362B/en unknown
  • 1988-02-10 CN CN88100863A patent/CN1017374B/zh not_active Expired
  • 1988-02-10 CS CS88834A patent/CS271480B2/cs unknown
  • 1988-10-10 FI FI884648A patent/FI884648A/fi not_active IP Right Cessation
  • 1988-10-10 NO NO884517A patent/NO166814C/no unknown
• 1989
  • 1989-05-25 GR GR89300043T patent/GR890300043T1/el unknown
• 1990
  • 1990-11-19 GR GR90400938T patent/GR3002535T3/el unknown

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